Method of forming teeth of rasps



'(No Model.) 2 Sheets-Sheet 1.

P. SQSTOKES. METHOD OF FORMING TEETH 0F RASPS.

No. 408,936. Patented Aug. 13, 1889.

N. PETERS. "MD-WI. Wahinlbfl, DYC.

' (N M L) 2 SheetsSheet 2., V P. S. STOKES. METHODOP FORMING TEETH OE RASPS. vN0. 408,936.

Patented Aug. 13, 1889.

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l/VVEIVTOR ATTORNEY N. PEYERS. Phom-Litfngraphan Wahlngtpn D- G UNITED STATES PATENT OFFICE.

PHILIP S. STOKES, OF FREEIIOLD, NEIV JERSEY.

METHOD OF FORMING TEETH OF RASPS.

SPECIFICATION forming part of Letters Patent No. 408,936, dated August 13, 1889.

' Application filed March 16, 1889. Serial No. 303,568. (No model.)

To aZZ whom it may concern.-

3e it known that I, PHILIP S. STOKES, of Freehold, in the county of Monmouth and State of New Jersey, have invented a new and Improved Method of Forming Teeth on Rasp- Blanks, of which the following is a full, clear, and exact description. 7

In making rasps the blank of annealed or soft steel is wrought upon with a sharp-pointed punch or chisel to lift each tooth separately from the surface of the blank. After the teeth are formed the blank is tempered. In order that the rasp shall be of high grade, each tooth shall have a sharp cone-point and the teeth should be uniform in height and shape. This I have discovered, can be produced by machinery with the best results, giving the highest quality to the rasp only by a succession of blows delivered upon the punch-that is, by placing the point of the punch at the proper angle upon or near the blank and then forcing the point into the blank by a series of blows of regulated force or power delivered upon the punch. By my new method the point of each tooth is lifted from the surface of the blank by a first blow, and then the body of the tooth is formed by one or more succeeding blows, and the punch is at the same time permitted to swing back at its upper end, so that the point moves in a curve and has a distinct movement in the line of the length of the blank. The blow at the outset gives a sharp edge and delicate point to the tooth, which it will maintain while the remainder of the tooth is lifted by the succeeding blow or blows upon the punch, and by thus starting the point with an initial blow the wear on the punch-point is materially lessened, while each tooth will be increased in length and made more nearly perfeet.

WVhile various means may be employed for carrying out this method or process, I prefer to use the machine covered by my application for Letters Patent, Serial No. 287,298, which was allowed on the 7th day of January, 1889. I

In the accompanying drawings, Figure 1 is a sectional elevation of a portion of said machine. Fig. 2 is a detailed rear View of the same. Fig. 3 is a plan view of a part of a rasp made in accordance with my new process or method, and Fig. 4 is a sectional view of the same.

In any machine constructed to carry out my new method or process at least two hammers or strikers should be emyloyed, and while these might be of suitable weight to act by gravity alone I prefer to employ springactuated hammers, so that the force of the blow may be readily regulated. The machine I prefer to employ is provided with a light-stroke hammer A and a heavy-stroke hammer B, the former being actuated upon by a light spring A, the latter by a comparatively heavy spring B. These hammers are adapted to be lifted against the pressure of the said springs and dropped, one preceding the other, upon the anvil-frame 0, through which the blows are transmitted to the tool or punch D. The hammers are lifted by a cam E, formed with a short toe to to lift hammer A and with elongated toes I) to lift the hammer B. The punch is held in a stock F, pivoted on a rod G, and the upper end of the stock is held normally to vertical position by the plate d and spring cl, which yield under the stroke of the hammer B. The rod G is intermittently moved endwise back and forth by mechanism shown and described in my above-referred-to application to carry the punch across the blank II to form the rows of teeth. Theblank is held on a table J, which is intermittently moved up the main frame K by screw L and mechanism for turning the same shown and described in said application, and which need not be here set forth. The anvil-frame O has an up-and-down movement, as described in said application, to lift the tool above the blank after the formation of each tooth to permit the blank, and also the stock F, to be moved.

In forming each tooth the anvil-frame is held so that the point of the punch just clears the blank. The hammer is then caused to deliver alight blow upon the anvil, which sinks the point of the tooth into the surface of the blank and lifts a delicate and sharp point of metal. The heavy blow is then struck upon the anvil, which sinks the punch deep into the blank and lifts the body of the tooth. Under these blows the resistance to the punch overcomes the pressure of the spring (1, and the punch swings back at its upper end,which ICO causes the point of the tool to move forward out of its line of thrust, which movement in connection with the downward movement result in a curvilinear movements at the point. This produces a tooth with a comparatively shallow cut or cavity. By starting the tooth with an initial blow the point is made very perfect, delicate, and sharp, while the wear upon the punch-point is materially lessened.

Having thus fully described my invention, I claim and desire to secure by Letters Patcut- 1. The method or process herein described of forming teeth on rasp blanks by machinery, which consists in starting the point by an initial blow delivered upon the punch and then lifting the body of the teeth by a subsequent blow or a series of blows, substantially as described.

2. The method or process herein described of forming teeth on rasp-blaul s, which consists in starting the point by an initial blow delivered upon the punch and then forming the body of the tooth by a subsequent blow or series of blows, the punch being at the same time swung back at the top, substantially as and for the purposes set forth.

3. The process of forming the teeth upon rasp-blanks, which consists in starting the point of each tooth by an initial blow delivered upon the punch, the blow being accurately gaged to the same force or power for each tooth, and then lifting the body of each tooth by a subsequent blow or series of blows on the punch, this or these subsequent blows being also accurately gaged to the same force or power for each tooth, whereby the teeth of the rasp are made uniform, substantially as described.

PHILIP S. STOKES.

'itnesses:

WM. A. BARKALOW, .lonN II. S'roKEs, A. C. IIARTSHORNE. 

